The T-cell chemokine receptor CXCR3 is expressed highly in low-grade mycosis fungoides

Three chemokines, Mig, IP-10, and I-TAC, are expressed highly, in the epide rmis. We examined the expression of the receptor for these chemokines, CXCR 3, in cutaneous T-cell lymphoma. We compared CXCR3 expression with that of cutaneous lymphocyte antigen (CLA) and the activation marker CD30. CXCR3 wa s expressed by at least a subset of tumor lymphocytes in all 25 cases of lo w-grade mycosis fungoides IMF), with most cells positive in 20 cases. In pr ogressed or transformed MF, CXCR3 expression was noted in 5 of 22 cases. In 4 of 5 MF cases with sequential biopsy specimens, large cell transformatio n was accompanied by loss of CXCR3 expression. In contrast, CLA was express ed in 35 of 42 MF cases with no significant differences in expression level between low-grade and transformed cases. In other lymphomas, CXCR3 was exp ressed in 4 of 4 cases of lymphomatoid papulosis, 3 of 4 cases of CD8+ cuta neous T-cell lymphoma, and 3 of 6 cases of systemic T-cell lymphoma in skin , but not in 10 cases of cutaneous anaplastic large cell lymphoma. CXCR3 ex pression was associated with epidermotropic T-cell tumors but was largely a bsent in dermal-based tumors. This phenotypic change likely influences the loss of epidermal localization.